Kernel Module Removal

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Kernel modules are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This rule identifies attempts to remove a kernel module.

Rule type: query

Rule indices:

  • auditbeat-*
  • logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Linux
  • Threat Detection
  • Defense Evasion

Version: 7 (version history)

Added (Elastic Stack release): 7.8.0

Last modified (Elastic Stack release): 7.12.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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There is usually no reason to remove modules, but some buggy modules require it. These can be exempted by username. Note that some Linux distributions are not built to support the removal of modules at all.

Rule query

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event.category:process and event.type:(start or process_started) and
process.args:((rmmod and sudo) or (modprobe and sudo and ("--remove"
or "-r")))

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 7 (7.12.0 release)
  • Formatting only
Version 6 (7.11.2 release)
  • Formatting only
Version 5 (7.11.0 release)
  • Formatting only
Version 4 (7.10.0 release)
  • Formatting only
Version 3 (7.9.1 release)
  • Formatting only
Version 2 (7.9.0 release)
  • Updated query, changed from:

    event.action:executed and process.args:(rmmod and sudo or modprobe and
    sudo and ("--remove" or "-r"))